Method of agglomerating pulverulent ores



Patented Feb. 10, 1931' UNITED STATES PATENT OFFICE 'BRoR GHRISTIANSEN,or sMEnJEB AcKE v, SWEDEN- METHOD OF AGGLOMERATING PULYERULENT ORES NoDrawing. Application filed October 30, 1928, Serial No, 316,113, and inSweden November 8, 1927.

In agglomerating pulverulent iron ores, by

, sinteringor briquetting it has been established that pulverulent.magnetites almost without exception are easyto sinter or briquettewhile pulverulent'hematites often can-.

not be agglomerated .in this way. Also in the case that the sintering orbriquetteing of pulverulent hematite. ores really succeeded theresulting product, as a rule, had a very low mechanical resistance. Ithas been tried to obtain a satisfactory result by admixing to thehematite ore, pulverulent magnetite or other materials, preferablylimestone or quartz. It has also been proposed to reduce the hematite tomagnetite before sintering it. The low or totally absent power ofagglomeration in pulverulent hematite in comparison with pulverulentmagnetite has not previously been indisputably explained.

My experiments have'shown that pulverulent hematite which cannot besintered or briquetted in the usual well-known manner owing to theirdefective power of agglomeration can be well agglomerated if the ore isfirst finely crushed to a flour-like product corresponding to agrainsize of 0.04 milli meters or'less. Howeventhe ore shall not becrushed to a colloidal or slimy consistency.

e3 pulverulent hematites, as a matter of fact, in

The defective power of agglomeration of of pressing briquettes which aresintered by heating, the agglomeration in sintering pans by combustingfuel admixed to the ore etc.

In carrying out my method practically it is not necessary to crush allof the pulverulent ore to'the' fineness of flour. It is sufiicient togive such fineness only to such a great portion thereof that the productin its entirety has an adhesion corresponding approximately to thatgenerally characteristic of flour-like products.

What I claim is i 1. A method of agglomerating pulverulent hematites,comprising crushing the pulverulent ore to such fineness that the mainportion of the mass has a grain size of 0.04 millimeters or less but nota colloidal or slimy name.

BROR GHRISTIANSEN. v

r so the first place seems to depend upon the failing adhesive power ofthe greater grains of the pulverulent ore. -But if the ore issufl'iciently finely ground the grains of the pul- 35 verulent oreobtain such adhesive power also in dry state and sinter together withoutdifli culty, when heated.

The principle of my inventionis, therefore,

that in agglomerating pulverulent hematites erated by sintering,briquetting or any other way the grains of the ore are rendered adhesiveto each other by being subjected to a fine-crushing carried very far butnot'to the colloidal state and thereafter the agglomeras tion is carriedout without difliculty.

My invention is applicable to all known methods of agglomeratingpulverulent ores *hy heating and to all such methods combined u with areduction of the ore, such as the method which could not hithertobesuitably agglom-.

